GDB server remote command handler.
GDB server remote command handler.

- Refactored Rcmd handler into separate function.
- Handling, or at least accepting and ignoring, all OpenOCD commands
  send by the GNU ARM Eclipse OpenOCD plugin.
- Handling 'arm semihosting enable'.
- Some minor cleanup of the Rcmd code.

Signed-off-by: Chris Reed <ddbbf6166888b293a1c3f06933a7a3227dbb7a9f@freescale.com>

flit/pyOCD,oliviermartin/pyOCD,mbedmicro/pyOCD,bridadan/pyOCD,mesheven/pyOCD,0xc0170/pyOCD,tgarc/pyOCD,wjzhang/pyOCD,devanlai/pyOCD,0xc0170/pyOCD,mbedmicro/pyOCD,pyocd/pyOCD,adamgreen/pyOCD,oliviermartin/pyOCD,bridadan/pyOCD,c1728p9/pyOCD,matthewelse/pyOCD,wjzhang/pyOCD,0xc0170/pyOCD,adamgreen/pyOCD,c1728p9/pyOCD,adamgreen/pyOCD,tgarc/pyOCD,oliviermartin/pyOCD,devanlai/pyOCD,flit/pyOCD,mbedmicro/pyOCD,mesheven/pyOCD,pyocd/pyOCD,wjzhang/pyOCD,tgarc/pyOCD,matthewelse/pyOCD,devanlai/pyOCD,bridadan/pyOCD,mesheven/pyOCD,c1728p9/pyOCD,matthewelse/pyOCD